Patent GB-803791-A (GB)
Title: Improvements in or relating to locking and releasing devices
IPC: H01H3/30
Filed: 1955-02-28
Abstract: 803,791. Toggle linkwork; locking levers; clutches. SIEMENS SCHUCKERTWERKE A.G. Feb. 28, 1955 [Feb. 27, 1954; March 31, 1954], No. 5961/55. Classes 80 (2) and 80 (3). [Also in Group XXXVII] In a rapidly-collapsible locking device, particularly for high voltage switch mechanism or for clutches, a part 12, Fig. 1, is supported relatively to a housing 6 against the action of a spring force P by two or more locking rollers 1, 2 which are pressed against a planar wall 9 by spring, magnetic or pneumatic means and act through convex abutments formed by further rollers 3, 4. A releasing thrust is applied by a pin 17 to one or more of the rollers 1, 2 to cause the line of rollers to collapse. The part 12 is coupled to the contacts of a switch, a switch spring providing the force P. In a modification, Fig. 4 (not shown), the force P is applied to the part 12 by a lever having a cam connection with a spring-loaded lever on a switch shaft and the locking rollers 1, 2 are biased by individual adjustable springs, vents being provided to allow air movement as the rollers are displaced. In another modification four rollers, each associated with a respective release pin, are located between two abutment rollers so that the device may be collapsed by any of four independent quantities. For locking angularly movable levers 109, 107, Fig. 6, the end of a shaft carrying the lever 109 is recessed to receive two spring-loaded locking rollers which, in the locked position shown, hold two outer abutment rollers in recesses in a surrounding member 103 carrying the lever 107. Locking is released by a pin 106. In a modification the pin 106 is actuated by compressed air fed along an axial bore in the shaft and controlled by a two-way cock which may be actuated by hand or automatically. The levers 107, 109 may be omitted so that the device forms a clutch between rotating parts. The recesses receiving the rollers may be elongated as shown in dotted lines to provide a degree of angular lost motion between the clutch parts and means be provided to actuate the pin 106 automatically to disconnect the clutch should one part commence to overtake the other. The clutch is then automatically re-engaged if the overtaking part subsequently lags. In applying the lever-locking device to the control of a spring-opened contact 128, Fig. 12, which forms part of an overload switch and is linked to the lever 107, a spring-loaded pawl 108, on a fixed pivot, engages the outer roller 115 to prevent anticlockwise movement of the locked-together levers 109, 107 and thus prevent opening of the contact 128 by the spring 127. On overload in the controlled circuit the pin 106 is shifted to collapse the line of rollers 115 and thus unlocks the two levers so that the spring 127 swings the lever 107 and opens contact 128. The pawl 108 continues to engage the outer roller 115, and thus hold the lever 109, until the contact 128 is fully open, when a projection 103n lifts the pawl 108 and allows a spring 109c to pull the lever 109 into alignment with the lever 107. The rollers 115 may then return to the straightline position to lock the levers together again so that a force may be applied (by hand, electric motor or compressed air) to the lever 109 to re-close the contact 128. It is stated that the device may be modified so that the lever 109 is linked to the switch contacts and is actuated by the lever 107.